In printing characters or symbols with a matrix print head, customarily the print wires have their leading ends disposed in confronting relation to the record of print medium so that as the print head is advanced across the page selected wires are actuated to drive their leading ends into the print medium to form a series of dots which make up each character or symbol. Generally, the print wires must be actuated several times in forming each character or symbol and, since they are driven along their lengths are highly subject to wear, misalignment and uneven impressions as the print head is advanced across the page. In forming a series of closely spaced dots, the leading ends of the print wires are arranged in closely spaced relation to one another and necessarily must diverge rearwardly away from the closely spaced leading ends in order to afford sufficient spacing for insertion of the trailing end of each print wire in an actuator. Typically the actuators are of the solenoid or electromagnetic type, and the trailing end of each print wire is affixed to the armature so that when the armature is energized it will cause the print wire to advance forwardly in driving its leading end into contact with the print medium. As a result, the print wires must be of sufficient length to permit gradual divergency away from their leading ends to a point which will afford sufficient spacing between the electromagnetic actuators. It is conventional to mount or guide the print wires so as to be disposed on a radius of curvature corresponding to its elastic curve in order to minimize the support required for the print wire along its length as it is driven forwardly and away from the print medium. In the past, however, this has been done by positioning the wires in the same plane and diverging the wires rearwardly away from the leading ends at different angles with respect to the print medium, as a result of which the print wires were displaced at different angles with respect to the paper and had a tendency to make uneven impressions when actuated by their respective electromagnetic drivers. Moreover, disposition of the drivers in a single plane or line necessitated support along the substantial length of the print wire, especially of the outer print wires, to assure that the wires would remain in the desired path when driven into the print medium.
Another problem associated with wire matrix print heads has been that of maintaining the print wires in a selected guide path to most efficiently drive the wires with a minimum of wear while devising a print head which would occupy a minimum of space and be as lightweight as possible. This is especially important in smaller machine applications, such as, calculator printers of the type set forth and described in my copending application Ser. No. 527,603, filed 27 Nov, 1974 and entitled SERIAL IMPACT CALCULATOR PRINTER.